Constraining Primordial Black Holes Based on The Dynamics of Neptune

The nature of dark matter (DM) is unknown. One compelling possibility is DM being composed of primordial black holes (PBHs), given the tight limits on some types of elementary particles as DM. Here, we show that Neptune's orbital eccentricity places constraints on PBHs in the sub-solar mass window. We also derive new limits on the local abundance of rogue interstellar planets.